Towable impact attenuator

ABSTRACT

A crash attenuator includes a crash cushion having a front end, a rear end, and a trailer hitch component disposed adjacent the front end. The trailer hitch component is capable of being secured to a mating hitch component located on the towing vehicle, such that hitch components are capable of being rotated relative to each other about a substantially vertical axis. The crash attenuator further includes at least one wheel supporting the crash cushion. The wheel is rotatable about a substantially horizontal axis and is spaced rearwardly from hitch component. One or more tethers are positioned on opposite sides of the hitch component and are moveable relative to one or more guides connected to the crash cushion.

This application is a continuation of prior U.S. patent application Ser.No. 12/976,210, filed Dec. 22, 2010, now U.S. Pat. No. 8,136,830 whichwas a divisional of prior U.S. patent application Ser. No. 11/272, 352,filed Nov. 10, 2005, now U.S. Pat. No. 7,874,572 which claims thebenefit of U.S. Provisional Application No. 60/642,699, filed Jan. 10,2005, the entire disclosure of which is hereby incorporated herein byreference.

FIELD OF THE INVENTION

This invention relates to a vehicle system capable of attenuating energyduring a crash, and in particular to a crash cushion capable of beingtowed behind a vehicle.

BACKGROUND

Crash cushions and attenuators are commonly secured to vehicles, such astrucks, operating on the roadways to protect other vehicles and theiroccupants during an impact. Often, such attenuators are secured to therear of the truck, or other vehicle, and are cantilevered rearwardlytherefrom. As such, the mounting structure of the attenuator must beable to support the shear and moment loads created by the cantileveredcrash cushion, thereby leading to increased costs associated with themanufacture thereof. Moreover, attachment of the attenuator may becumbersome.

SUMMARY

In one aspect, a crash attenuator includes a crash cushion having afront end, a rear end and a trailer hitch component disposed adjacentthe front end. The trailer hitch component is secured to a mating hitchcomponent located on the towing vehicle, such that hitch components arecapable of being rotated relative to each other about a substantiallyvertical axis, for example during turns or backing operations. The crashattenuator further includes at least one wheel supporting the crashcushion. The wheel is rotatable about a substantially horizontal axisand is spaced rearwardly from the substantially vertical axis. The crashattenuator further includes at least one restraint element operablebetween at least a disengaged condition, wherein the crash cushion iscapable of rotating about the substantially vertical axis, and anengaged condition, wherein the at least one restraint element constrainsrotation of the crash cushion about the substantially vertical axis.

The foregoing paragraphs have been provided by way of generalintroduction, and are not intended to limit the scope of the followingclaims. The presently preferred embodiments, together with furtheradvantages, will be best understood by reference to the followingdetailed description taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of a towable crashattenuator without a hitching system shown.

FIG. 2 is a top view of the attenuator shown in FIG. 1.

FIG. 3 is a side view of the attenuator shown in FIG. 1.

FIG. 4 is a top view of a towable crash attenuator having a firstembodiment of a hitching system.

FIG. 5 is a side view of the attenuator shown in FIG. 4.

FIG. 6 is a top view of a towable crash attenuator having a secondembodiment of a hitching system.

FIG. 7 is a side view of the attenuator shown in FIG. 6.

FIG. 8 is an alternative embodiment of an extensible/compressiblerestraint element.

FIG. 9 is a top view of a towable crash attenuator having a thirdembodiment of a hitching system.

FIG. 10 is a side view of the attenuator shown in FIG. 9.

FIG. 11 is a top view of a towable crash attenuator having a fourthembodiment of a hitching system.

FIG. 12 is a side view of the attenuator shown in FIG. 11.

FIG. 13 is a top view of a towable crash attenuator having a fifthembodiment of a hitching system.

FIG. 14 is a side view of the attenuator shown in FIG. 13.

FIG. 15 is a top view of a towable crash attenuator having a sixthembodiment of a hitching system.

FIG. 16 is a side view of the attenuator shown in FIG. 15.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

The term “longitudinal” refers to the lengthwise direction 2 between thefront and rear of a crash cushion 10, and is aligned with and defines anaxial impact direction generally parallel to the arrow indicatingtraffic flow in FIG. 1-3. The term “front,” “forward,” “forwardly” andvariations thereof refer to the position or orientation relative to theend 4 of the crash cushion located adjacent or proximal to the towingvehicle and distal from the end that is initially impacted during anaxial impact, while the term “rear,” “rearward,” “rearwardly” andvariations thereof refer to the position or orientation relative to thetail or end 6 of the crash cushion located distal from the towingvehicle and which is initially impacted.

Turning now to the drawings, FIGS. 1-3 show perspective views of a crashcushion 10 incorporating preferred embodiments of this invention. In oneembodiment, the crash cushion includes a frame 28 defining first andsecond bays 8,12, with energy dissipating cartridges 14 disposed in thefirst and second bays. Suitable crash cushions are disclosed for exampleand without limitation in U.S. Pat. Nos. 6,092,959 and 6,579,034 andU.S. patent application Ser. No. 10/628,319, all of which are herebyincorporated herein by reference in their entirety. Suitable crashcushions also include the Safe-Stop™ 180 truck mounted attenuator, theSafe-Stop TMA® crash attenuator, the Alpha 70k™ truck mountedattenuator, the LS-Pro™ truck mounted attenuator, the Alpha 60MD® truckmounted attenuator and the Alpha 2001 MD TMA® crash attenuator allavailable from Energy Absorption Systems, Inc., located in Rocklin,Calif., the assignee of the present application. Of course, it should beunderstood that other embodiments of crash cushions, including singlebay or cartridge embodiments, with or without frames, would also work.

In one embodiment, as shown in FIGS. 1-3, an axle assembly is secured toa frame structure 16 disposed between and connecting the first andsecond bays 8,12. In one embodiment, the intermediate frame structure 16is substantially rigid, and does not collapse or become crushed during avehicle impact. In one embodiment, the axle assembly is atorsion/suspension axle assembly, such as a Torflex® axle, whichincludes a main axle 18 and a pair of wheel axles 22 secured theretowith a pair of arms 24 that rotate against a biasing force of a torsionspring (not shown). Of course, it should be understood that other axleconfigurations, such as rigid/straight axle, or other suspension axles,including for example and without limitation leaf or compression springswith dampening systems, would also work. Two wheels 20 are secured tothe axles 22 on opposite ends of the axle 18. The wheels rotate about ahorizontal axis of rotation 26. The wheels 20 are preferably spaced fromthe front end 4 of the crash cushion and are positioned to carry theload or weight of the crash cushion. The wheels, which are engaged withthe ground, help guide the crash cushion in the longitudinal direction 2during an impact.

Referring to FIGS. 4-7 and 9-14, the crash cushion includes a firsthitching component, shown as a tongue 30 having one end 44 secured tothe crash cushion, e.g., the frame, and an opposite free end 40. Thefirst end can be rotatably secured to the crash cushion, ornon-rotatably fixed thereto. In one embodiment, a pair of brace members32 extend from the crash cushion and are secured to the tongue distalfrom the first end 44.

A vehicle 34, such as a truck, preferably has a pair of frame rails 36extending in the longitudinal direction 2. The frame rails are spaced onopposite sides of a hitching component 38. The hitching component caninclude for example and without limitation, a hook, ball, fifth wheel orother known and suitable devices. The free end 40 of the tongue isconfigured to mate with the truck hitching component 38 and can includefor example and without limitation, a loop, a socket or a matingstructure for the fifth wheel. The two hitching components 38, 40 areconfigured to allow relative rotation about a vertical axis 46, suchthat the crash cushion can rotate relative to the tow vehicle duringtowing or backing operations. The hitching components 38, 40 also permitrelative rotation about a horizontal axis, such that the crash cushioncan rotate relative to the towing vehicle about the horizontal axis, forexample when being towed over a bump or through a dip in the roadway.

Referring to FIGS. 4-16, one or more restraint elements 42 are connectedor engaged between the crash cushion 10 and the towing vehicle 34. Inparticular, first and second restraint elements are positioned onopposite sides of the hitching component, shown as the tongue 30. Invarious embodiments, a single restraint element may be used, or morethan two restraint elements may be used.

Referring to FIGS. 4 and 5, the restraint elements 42 are shown as rigidstruts. The struts can be moved to a disengaged condition, wherein oneor both ends of the strut are disengaged from the vehicle 34 and/orcrash cushion 10. For example, in one embodiment, the struts have oneend 48 pivotably secured to the crash cushion about a vertical axis. Thestruts, and in particular the ends 48, are pivoted sidewardly to adisengaged condition/position wherein the struts do not restrain therotation of the crash cushion relative to the towing vehicle about thevertical axis 46. In another embodiment, the struts are pivoted upwardlyor downwardly about a horizontal axis. When in this travel, non-impactposition, wherein the restraints are in the disengagedcondition/position, the truck and trailer can negotiate tight turns andbacking situations.

When the vehicle is in a position where crash protection is desired, forexample when parked along the side of a highway, the struts 42 arepivoted into an engaged condition or position, preferably with the freeends 50 thereof being secured to the vehicle adjacent respective framerails 36, for example with a pin, latch or other device, such that theimpact load is transferred to the frame rails. In the engaged condition,the restraint elements constrain rotation of the trailer crash cushionrelative to the tow vehicle, and rotation of the first hitchingcomponent relative to the second hitching component, about the verticalaxis. The terms “constrain” and “restrain,” and variations thereof,refer to substantially preventing or restricting relative movement.

In one embodiment, as shown in FIG. 5, the restraint elements 42 arepositioned in a substantially horizontal plane spaced above a horizontalplane of the hitch tongue 30, and preferably in alignment with the framerails 36. It should be understood that the struts could alternatively bepivotally secured to the vehicle and rotated into the engagedcondition/position by releasably securing the struts to the crashcushion. In yet another embodiment, both ends 48, 50 of the strut arereleasably secured to the vehicle and crash cushion respectively, suchthat the struts are completely removed and disconnected from the vehicleand crash cushion, whereinafter they can be stored on the truck ortrailer when in the disengaged condition/position.

Referring to FIGS. 6 and 7, the restraint elements 42 are configured asextensible/compressible cylinders, which are used in the sameorientation as the rigid struts when in the engaged condition/position,but remain in place during impact conditions and during travel orbacking, i.e., the restraint elements 42 are secured between the crashcushion 10 and the tow vehicle 34 while in the engaged and disengagedconditions. The cylinders are preferably fluid cylinders, including forexample and without limitation pneumatic and hydraulic cylinders. In oneembodiment, two restraint element cylinders are plumbed together andinclude a single valving arrangement 52 that permits fluid flow to andfrom the piston cylinders during normal turning or backing, such thatthe restraint elements 42 can be extended or compressed, i.e., theirlength can be varied. During an impact, however, the valving arrangement52 constrains or limits the fluid flow, thereby locking the cylinders,or putting them in an engaged condition, such that they act as rigidmembers and prevent rotation of the crash cushion 10 relative to thevehicle 34, and rotation of the trailer hitch component 40 relative tothe vehicle hitch component 38, about the vertical axis 46. In oneembodiment, the valving arrangement 52 includes a restrictive orificethat precludes instantaneous fluid flow therethrough.

In another embodiment, a trailer surge activator 90 is connected to andincorporated into the valving arrangement 52. The surge activator closesone or more valves at each cylinder, or single valve connected to bothcylinders, during an impact. As shown in FIGS. 6 and 7, two-stagetelescoping cylinders are used as the restraint element 42 to achieve 90degrees rotation travel of the crash cushion relative to the tow vehicleabout the vertical axis. In other embodiments, a single stage, orcylinders with more than two-stages can be used. As shown in FIG. 8, apair of single-stroke cylinders 54 can be secured to each other to forma single restraint element, thereby providing increased travelcapability. In this embodiment, the ram extensions 56 from the cylindersextend in opposite directions from the assembly.

It should be understood that a single valve can control the flow to bothrestraint elements, or that each restraint element can have its owncontrol valve. Of course, more than two valves can also be used.Preferably, both ends 48, 50 of the restraint elements are pivotallysecured to the crash cushion and the vehicle respectively, again withthe ends of the cylinders secured to the vehicle preferably beingpositioned adjacent the frame rails 36 such that the loads from thecylinder are transferred to the frame rails.

Referring to FIGS. 9 and 10, a telescoping, or extensible/compressibletrailer tongue 58 is disclosed. The telescoping trailer tongue includesa shear element 60, such as a shear pin, that is sheared or breaks uponimpact by a vehicle against the crash cushion, thereby allowing thetongue to collapse or compress and travel forward such that the lengththereof is reduced from a first to a second length until impact pads 62on the trailer strike or engage corresponding impact pads/elements 64 onthe rear of the truck. The impact pads/elements 62, 64 define therestraint element. When the pads 62, 64 are engaged on one or both sidesof the trailer/truck, such that the restraint elements are in theengaged condition/position, rotation of the crash cushion trailer withrespect to the truck is constrained.

Referring to FIGS. 11 and 12, each of the restraint members 42, shown asfluid cylinders, are secured to an intermediate portion 66 of thetrailer hitch tongue 30. In this application, the fluid cylinder islocated above the trailer tongue and mount on the truck outboard asexplained above. The restraint elements 42 may have to be angled fromthe tongue to the mounting portion of the truck, or different bracketscan be secured to one or both of the tongue and truck to accommodate theheight differential. For example, in one embodiment (now shown), bracketis secured to the frame rail and includes a portion aligned in the sameplane with the tongue. By attaching the cylinders to the tongue, aconvention, single-stage/stroke cylinder can be used while stillpermitting rotation of the crash cushion relative to the vehicle and thetrailer hitch component relative to the vehicle hitch component when therestraint elements are in the disengaged condition.

In the embodiments of FIGS. 6-12, the restraint elements primarily workin compression to constrain rotation of the trailer crash cushionrelative to the two vehicle, such that one or the other or both of therestraint elements are constraining such rotation. Of course, therestraint elements also provide some tension resistance on the otherside of the hitching component. The restraint elements of FIGS. 3 and 4work both in tension and compression.

Referring to FIGS. 13 and 14, the restraint element 42 works almostexclusively in tension. In particular, a properly sized tether 68, forexample a cable or chain, has one end 72 attached on one side of thetruck, e.g. adjacent a frame rail 36. The tether 68 travels past and isdisposed on a pair of horizontally spaced guides 70 positioned onopposite sides of the front portion 4 of the crash cushion, e.g., on thetrailer frame, and back to the other side of the truck where the otherend 74 of the tether is secured, e.g., adjacent the other frame rail 36.During normal trailering and backing motions, the restraint element, ortether 68, is in a disengaged condition, such that the trailer crashcushion 10 is able to rotate from side to side about the vertical axis46, thereby translating the tether element 68 relative to the guides 70.

During an impact situation, a trailer surge activator 90, or othersensor, actuates a brake 76, which grips the tether element 68 andprevents movement thereof relative to the guides 70. The immobile tetherelement 68 is thereby put in an engaged condition, such that the portionthereof opposite the direction of rotation is placed in tension andrestrains rotation of the trailer crash cushion 10 relative to thevehicle 34 about the vertical axis 46.

Referring to FIGS. 15 and 16, a free end 80 of each of a pair of tetherelements 82 are connected to opposite sides of the vehicle, for exampleadjacent the frame rail 36. The other end of the tether elements aregathered by a retraction mechanism 84, which winds up or lets out thetether element 82 during normal trailering movements, i.e., when in thedisengaged condition. In the event of an impact, the retractionmechanism 84 grips or brakes the tether element 82, thereby putting therestraining element in an engaged condition, either by activation from asurge activator 90 or by centrifugal motion of elements within themechanism (similar to a seat belt). The retraction mechanism 84 therebyrestrains the movement of the tether element 82 and the rotation of thecrash cushion 10 relative to the vehicle 34, or rotation between therespective hitch components 38, 40, about the vertical axis 46.

In another embodiment (not shown), a custom hitch assembly incorporatesbraking elements to prevent rotation between the hitch componentsthemselves. During an impact condition, a surge activator, or othersensor/device, actuates a braking mechanism on the hitch therebyconstraining rotation between the hitch components which are in theengaged condition. For example, a friction brake assembly can beconfigured and incorporated into a fifth wheel assembly. In thisembodiment, the restraining element is the brake and hitch componentsthemselves, and does not require any additional struts, cylinders orcables. During regular towing or backing, the restraining elements areput in a disengaged condition.

In a similar embodiment (not shown), the hitch incorporates a hydraulicdamper. During normal trailering operations, wherein the restrainingelement is in the disengaged condition, the rotation of the trailerrelative to the truck is permitted by flow of fluid through a valvingarrangement in the hitch component. In the event of an impact, therestraining element is operable in the engaged condition, wherein theflow of fluid is restricted or stopped, for example by a signal from thesurge activator, such that the hitch components are constrained fromrotating relative to each other.

Although the present invention has been described with reference topreferred embodiments, those skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention. As such, it is intended that the foregoingdetailed description be regarded as illustrative rather than limitingand that it is the appended claims, including all equivalents thereof,which are intended to define the scope of the invention.

1. A crash attenuator comprising: a crash cushion comprising a frontend, a rear end, and a trailer hitch component disposed adjacent saidfront end; at least one wheel supporting said crash cushion, whereinsaid at least one wheel is spaced rearwardly from said trailer hitchcomponent; and a tether comprising a cable having opposite end portionspositioned on opposite sides of said trailer hitch component, saidopposite end portions each adapted for connection to a tow vehicle,wherein said tether is guided by at least one guide connected to saidcrash cushion and is moveable relative to said at least one guide whensaid tether is in a disengaged condition such that said opposite endportions are moveable toward and away from said at least one guiderespectively.
 2. The crash attenuator of claim 1 further comprising abrake operable to grip said tether in an engaged condition.
 3. The crashattenuator of claim 2 further comprising a surge activator coupled tosaid brake, wherein said surge activator actuates said brake to gripsaid tether.
 4. The crash attenuator of claim 1 wherein said tether isnon-moveable relative to said at least one guide when said tether is inan engaged condition.
 5. The crash attenuator of claim 1 wherein saidtether wraps around at least a portion of said at least one guide. 6.The crash attenuator of claim 1 wherein said at least one guidecomprises a pair of laterally spaced guides disposed on opposite sidesof a centerline defined by said trailer hitch component.
 7. A crashattenuator comprising: a crash cushion comprising a front end, a rearend, and a trailer hitch component disposed adjacent said front end; atleast one wheel supporting said crash cushion, wherein said at least onewheel is spaced rearwardly from said trailer hitch component; a pair ofguides coupled to said crash cushion and laterally spaced on oppositesides of a centerline defined by said trailer hitch component; and agenerally U-shaped tether comprising a cable having opposite endportions positioned on opposite sides of said hitch component, saidtether wrapped around said pair of guides and having an intermediateportion disposed between said guides, wherein said tether is moveablerelative to said guides when in a disengaged condition such that saidopposite end portions are moveable toward and away from said guidesrespectively.
 8. The crash attenuator of claim 7 further comprising abrake operable to grip said intermediate portion.
 9. The crashattenuator of claim 8 further comprising a surge activator coupled tosaid brake, wherein said surge activator actuates said brake to gripsaid intermediate portion of said tether.
 10. A crash attenuatorcomprising: a crash cushion comprising a front end, a rear end, and atrailer hitch component disposed adjacent said front end; at least onewheel supporting said crash cushion, wherein said at least one wheel isspaced rearwardly from said trailer hitch component; and a tethercomprising a chain having opposite end portions positioned on oppositesides of said trailer hitch component, said opposite end portions eachadapted for connection to a tow vehicle, wherein said tether is guidedby at least one guide connected to said crash cushion and is moveablerelative to said at least one guide when said tether is in a disengagedcondition such that said opposite end portions are moveable toward andaway from said at least one guide respectively.
 11. The crash attenuatorof claim 10 further comprising a brake operable to grip said tether inan engaged condition.
 12. The crash attenuator of claim 11 furthercomprising a surge activator coupled to said brake, wherein said surgeactivator actuates said brake to grip said tether.
 13. The crashattenuator of claim 10 wherein said tether is non-moveable relative tosaid at least one guide when said tether is in an engaged condition. 14.The crash attenuator of claim 10 wherein said tether wraps around atleast a portion of said at least one guide.
 15. The crash attenuator ofclaim 10 wherein said at least one guide comprises a pair of laterallyspaced guides disposed on opposite sides of a centerline defined by saidtrailer hitch component.
 16. A crash attenuator comprising: a crashcushion comprising a front end, a rear end, and a trailer hitchcomponent disposed adjacent said front end; at least one wheelsupporting said crash cushion, wherein said at least one wheel is spacedrearwardly from said trailer hitch component; a pair of guides coupledto said crash cushion and laterally spaced on opposite sides of acenterline defined by said trailer hitch component; and a generallyU-shaped tether comprising a chain having opposite end portionspositioned on opposite sides of said hitch component, said tetherwrapped around said pair of guides and having an intermediate portiondisposed between said guides, wherein said tether is moveable relativeto said guides when in a disengaged condition such that said oppositeend portions are moveable toward and away from said guides respectively.17. The crash attenuator of claim 16 further comprising a brake operableto grip said intermediate portion.
 18. The crash attenuator of claim 17further comprising a surge activator coupled to said brake, wherein saidsurge activator actuates said brake to grip said intermediate portion ofsaid tether.